Fibre optic cables are being used in greater and greater frequency in the telecommunication industry for conveying large amounts of data. During the course of using fibre optic cables, it is necessary to terminate and join the cables at various locations and connectors are used to facilitate such termination and connection. It is very important for the effective transmission of data that the fibre optic information carrier in the fibre optic cable be properly positioned when cables are joined or terminated. If a mismatch occurs between the fibre optics of two fibre optic cables, the transmission efficiency of the cable is severely degraded. It is important, therefore, that the fibre optic cable be securely attached to its connector so that the imposition of a pulling force on the cable will not cause the fibre optic therein to be improperly positioned. While fibre optic cable connectors are known in the prior art, they have not provided a very secure and relatively simple method of attachment to a fibre optic cable.
Turning briefly to FIGS. 1-3, there is shown in FIG. 1 a conventional fibre optic cable with the various portions thereof stripped a way to expose the underlying portions. The fibre optic 3 within the cable is encased in a fibre core 2 which in turn is protected by a multitude of long thin fibres 4 evenly placed around the circumferencial surface of the fibre core 2 and parallel to the center axis of optic fibre 3. The thin fibres 4 are held in place by an outer cover 1. The long thin fibres 4 may be made from the product known as Kevlar and typically inhibit the fibre optic cable from being stretched.
FIG. 2 depicts, in section, a typical prior art fibre optic connector coupled to a fibre optic cable. This connector is assembled on the cable by first removing portions of the various layers of the cable as generally shown in FIG. 1. The fibre optic 3 and its fibre core 2 are inserted in a hole 6 in the connector's main body, a ferrule 7 having first slipped over the exposed end of the cable. The exposed reinforcement fibres 4 are secured to the connector body 5 by the action of ferrule 7 being crimped against crimping section 8 thereby capturing fibres 4 therebetween. In prior art connectors, in lieu of crimping ferrule 7, it is also known to use an adhesive such as epoxy to capture reinforcement fibres 4 between the inner circumferencial surface of ferrule 7 and the outer circumferential surface of crimping section 8. In FIG. 2, numeral 9 refers to a coupling nut conventionally employed with connectors.
It might appear that a connector manufactured and assembled as described with reference to FIG. 2 would provide a connector-cable joined of theoretically high strength. However, in reality, high strength is not obtained due to the difficulty in making up the connection between the connector and the cable. Namely, when using the prior art connector, the reinforcing fibres 4 tend to collect on one side or the other of the circumferential surface of crimping section 8 as is depicted in FIGS. 3a and 3b. When a connector is joined to a cable with the reinforcing fibres bunched on one side of the connector and the cable-connector joint is placed in tension, the pulling force applied to the cable is unbalanced between the side having more reinforcing fibres 4 and the side having fewer reinforcing fibres 4. The net result is a decrease in the strength of the connector-cable joint.
It is difficult to assemble the prior art connector to a fibre optic cable without the reinforcing fibres 4 becoming disarranged as shown in FIGS. 3a and 3b. This is due to the fact that it is the outer cover 1 which holds fibres 4 in place and when the outer cover 1 is partially removed to assemble the connector to the cable, there is essentially nothing to hold the fibres 4 in place. When the connector is installed as shown in FIG. 2, this disrupts the positions of fibres 4, not only in the exposed portion, but also to a certain extent for a distance under the outer cover 1. This disturbance often results in the fibres 4 becoming disarranged as shown in FIGS. 3a and 3b. Additionally, it has been found that it is rather difficult to manually rearrange fibres 4 so that they are equally spaced around a connector (so that they resemble the spokes of an umbrella). The disarrangement of fibres 4 becomes the greatest when the end portion of the connector body 5 contacts the end portion of the outer cover 1 as the connector is installed on the cable.